Arc detection apparatus using electrical energy

Abstract

An arc detection apparatus is provided. The arc detection apparatus detects an arc using an electrical energy, eliminates the possibility of a false arc detection caused by noise due to a power environment, increases accuracy of arc detection, and prevents fires that may occur in a home or an industrial site due to an arc occurrence.

What is claimed is: 
     
       1. An arc detection apparatus comprising:
 a rectifier configured to rectify an output signal of a current sensor (CS); 
 a current waveform shaper configured to compare an output signal of the rectifier to a reference value and shape a current in a comparison waveform, wherein the output signal is saturated when the output signal is greater than or equal to the reference value and is cut-off when the output signal is less than the reference value; 
 an electrical energy calculator configured to calculate an electrical energy from an output signal of the current waveform shaper and an output signal of a voltage sensor; 
 an arc determiner configured to compare an electrical energy, which is an output of the electrical energy calculator, to a reference electrical energy determined on the basis of an electrical energy for a predetermined period and determine whether an arc has occurred; and 
 an output unit configured to receive an electrical signal from the arc determiner when an arc occurs and output whether an arc has occurred. 
 
     
     
       2. The arc detection apparatus of  claim 1 , wherein the current waveform shaper includes an amplifier configured to amplify the output signal of the rectifier to be saturated. 
     
     
       3. The arc detection apparatus of  claim 2 , wherein the electrical energy calculator further includes a first current electrical energy calculator configured to receive the output signal of the current waveform shaper and an instantaneous voltage signal, which is an output of the voltage sensor, as inputs and calculate an electrical energy. 
     
     
       4. The arc detection apparatus of  claim 3 , wherein the arc determiner further includes:
 an integrator configured to output an electrical energy signal obtained by integrating outputs of a first current electrical energy calculator for a predetermined period; and 
 a first comparison unit configured to output a result signal obtained by comparing the output of the integrator to the output of the first current electrical energy calculator. 
 
     
     
       5. The arc detection apparatus of  claim 2 , wherein the electrical energy calculator further includes:
 a first analog-to-digital (A/D) converter configured to convert an analog current signal, which is an output of the amplifier, into a digital signal; and 
 a second current electrical energy calculator configured to receive an output signal of the first A/D converter and an instantaneous voltage signal, which is an output of the voltage sensor passing through the first A/D converter, and calculate an electrical energy. 
 
     
     
       6. The arc detection apparatus of  claim 5 , wherein the arc determiner further includes:
 a moving average filter configured to calculate an average electrical energy during a plurality of cycles by receiving an output signal of the second current electrical energy calculator as an input; and 
 a second comparison unit configured to output a result signal obtained by comparing an output of the moving average filter to an output of the second current electrical energy calculator. 
 
     
     
       7. The arc detection apparatus of  claim 1 , wherein the current waveform shaper, which shapes the current in the comparison waveform by comparing a preset reference value to a value obtained by over-amplifying the output signal of the rectifier, further includes:
 a second A/D converter configured to convert an analog current signal which, is an output of the rectifier, into a digital signal; and 
 a signal processor configured to output a logic value “1” when an output signal of the second A/D converter is greater than or equal to the reference value and output a logic value “0” when the output signal of the second A/D converter is less than the reference value. 
 
     
     
       8. The arc detection apparatus of  claim 7 , wherein the electrical energy calculator further includes a third electrical energy calculator configured to receive a current signal, which is an output of the current waveform shaper, and an instantaneous voltage signal, which is an output of the voltage sensor passing through an A/D converter, and calculate an electrical energy. 
     
     
       9. The arc detection apparatus of  claim 8 , wherein the arc determiner further includes:
 a moving average filter configured to calculate an average electrical energy during a plurality of cycles by receiving an output signal of the third electrical energy calculator as an input; and 
 a third comparison unit configured to output a result signal obtained by comparing an output of the moving average filter and an output of the third electrical energy calculator. 
 
     
     
       10. The arc detection apparatus of  claim 1 , further comprising a circuit breaker configured to cut an alternating current (AC) power line off from the arc determiner when an arc occurs. 
     
     
       11. The arc detection apparatus of  claim 1 , further comprising a circuit breaker configured to cut an AC power line off from the arc determiner when an arc has occurred and reconnect the AC power line to the arc determiner after a predetermined time. 
     
     
       12. The arc detection apparatus of  claim 1 , further comprising a circuit breaker configured to cut an AC power line off from the arc determiner when an arc has occurred and reconnect the AC power line to the arc determiner after a predetermined time, wherein the circuit breaker maintains the cut-off state without the reconnection of the AC power line after the cut-off and reconnection are repeated a predetermined number or more of times within a predetermined time.